[CSS][Feature request] Add Kibana Configuration and Cluster Snapshot config

[valentin-dubreuil]

Problem

In the ressource flexibleengine_css_cluster, it seems that we can't configure cluster snapshot as in the huaweicloud_css_cluster, because it's missing the arguments that we can configure in FE web interface.

https://github.com/FlexibleEngineCloud/terraform-provider-flexibleengine/blob/master/flexibleengine/resource_flexibleengine_css_cluster_v1.go#L143-L162

"backup_strategy": {
	Type:     schema.TypeList,
	Optional: true,
	MaxItems: 1,
	Elem: &schema.Resource{
		Schema: map[string]*schema.Schema{
			"start_time": {
				Type:     schema.TypeString,
				Required: true,
			},
			"keep_days": {
				Type:     schema.TypeInt,
				Optional: true,
				Default:  7,
			},
			"prefix": {
				Type:     schema.TypeString,
				Optional: true,
				Default:  "snapshot",
			},
		},
	},
},

https://github.com/huaweicloud/terraform-provider-huaweicloud/blob/master/huaweicloud/services/css/resource_huaweicloud_css_cluster.go#L190-L206

"bucket": {
	Type:     schema.TypeString,
	Optional: true,
	Computed: true,
},

"backup_path": {
	Type:     schema.TypeString,
	Optional: true,
	Computed: true,
},

"agency": {
	Type:     schema.TypeString,
	Optional: true,
	Computed: true,
},

Kibana public access configuration is not possible in FE but in huaweicloud it's possible.
                                                                                                  
https://github.com/huaweicloud/terraform-provider-huaweicloud/blob/master/huaweicloud/services/css/resource_huaweicloud_css_cluster.go#L261-L289

"kibana_public_access": {
	Type:         schema.TypeList,
	Optional:     true,
	MaxItems:     1,
	RequiredWith: []string{"password"},
	Elem: &schema.Resource{
		Schema: map[string]*schema.Schema{
			"bandwidth": { // Mbit/s
				Type:     schema.TypeInt,
				Required: true,
			},

			"whitelist_enabled": {
				Type:     schema.TypeBool,
				Required: true,
			},

			"whitelist": {
				Type:     schema.TypeString,
				Optional: true,
			},

			"public_ip": {
				Type:     schema.TypeString,
				Computed: true,
			},
		},
	},
},

It seems also that node_config is deprecated on huaweicloud so it could be good to implement is replacement ess_node_config in FE

[ShiChangkuo]

@valentin-dubreuil those features depend on v2 APIs which are not supported in FE.